Positioning of Methanosaeta and Methanosarcina spp. within the microstructure of carbohydrate-fed anaerobic granules

NRC publication: Ye

Ultrastructure of a bio-electrolytic methanogenic-methanotrophic granular biofilm for the complete degradation of tetrachloroethylene in contaminated groundwater

NRC publication: Ye

Biodegradation of pentachlorophenol in a continuous anaerobic reactor augmented with Desulfitobacterium frappieri PCP-1

In this work, a strain of anaerobic pentachlorophenol (PCP) degrader, Desulfitobacterium frappieri PCP-1, was used to augment a mixed bacterial community of an anaerobic upflow sludge bed reactor degrading PCP. To estimate the efficiency of augmentation, the population of PCP-1 in the reactor was enumerated by a competitive PCR technique. The PCP-1 strain appeared to compete well with other microorganisms of the mixed bacterial community, with its population increasing from 106 to 1010 cells/g of volatile suspended solids within a period of 70 days. Proliferation of strain PCP-1 allowed for a substantial increase of the volumetric PCP load from 5 to 80 mg/liter of reaction volume/day. A PCP removal efficiency of 99% and a dechlorination efficiency of not less than 90.5% were observed throughout the experiment, with 3-Cl-phenol and phenol being observable dechlorination intermediates.NRC publication: Ye

In-situ simultaneous measurement of thickness, elastic moduli and density of thermal sprayed WC-Co coatings by laser-ultrasonics

A method for simultaneous nondestructive evaluation of WC-Co coating thickness, elastic moduli, and density is presented. The technique, known as laser-ultrasonics, is used to generate and detect surface acoustic waves in a noncontact and nondestructive manner. The surface acoustic wave velocity dependence on frequency is compared to a model and an optimization procedure is used to evaluate the coating properties. The results obtained demonstrate the ability of the technique to simultaneously determine such properties with a single and possibly in situ measurement.Peer reviewed: YesNRC publication: Ye

Microbial population dynamics in a CANOXIS and a UASB TCE-degrading bioreactor

Trichloroethylene (TCE), a commin soil and groundwater pollutant, can be biodegraded either in aerobic and anaerobic conditions. Tartakovsky et al. (2003) have shown recently that the TCE degradation performances were higher in the coupled aerobic/anaerobic bioreactor (CANOXIS) oxygenated with hydrogen peroxide (H\u2082O\u2082) at a sub-bactericidal concentration than in an upflow anaerobic sludge bioreactor (UASB). To understand the microbial ecology underlying the TCE degradation in those reactors, a molecular study of the microbial population dynamics and a phylogenetic characterization were conducted using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The two bacteria domains and the presence of functional genes for TCE degradation were investigated using appropriate primers.NRC publication: Ye

Characterization of Surface-Breaking Tight Cracks Using Laser-Ultrasonic Shadowing

A laser-ultrasonic method based on the shadowing effect is used for sizing and locating surface-breaking tight cracks in metals. The two laser spots are separated by a fixed distance to detect ultrasound propagating at oblique incidence with respect to the sample surface. The laser spots are scanned along the same line across the path of cracks on the cracking surface or opposite surface. The amplitude of the longitudinal or shear waves specularly reflected from the backwall is extracted from each signal to construct an amplitude profile. In the presence of a crack, the profile shows regions of reduced amplitude due to shadowing of the direct or reflected beam from the backwall. The sharp amplitude drop and the gentle signal recovery observed are well predicted by a model of crack tip diffraction. The crack depth can be simply determined by considering the immediate vicinity of the amplitude drop. Results are shown on a stainless steel sample having a variable depth slot as well as on a sample containing actual surface-breaking tight cracks having widths of less than 30 \u3bcmPeer reviewed: NoNRC publication: Ye

Treatment of PCE-contaminated waters in a lab- and pilot-scale bioelectrytic methanogenic-methanotrophic system. Paper M-32, in: B.C. Alleman and M.E. Kelley (Editors), Proceedings of the Eighth International In Situ and On-Site Bioremediation Symposium (Baltimore, Maryland; June 6-9, 2005). CD ROM ISBN 1-57477-152-3, Battelle Press, Columbus, OH, USA.

NRC publication: Ye

Thickness and grain size monitoring in seamless tube making process using laser-ultrasonics

Peer reviewed: NoNRC publication: Ye

Bremsstrahlung attenuation measurements in ilmenite loaded concretes

NRC publication: Ye

Structural and optical characterization of InP/Ga[sub x]In[sub 1 - x]As[sub y]P[sub 1 - y] quantum wells and interfacial layers

Several multiquantum wells of InP/GaxIn1 12xAsyP1 12y grown by chemical\u2010beam epitaxy have been studied by high\u2010resolution x\u2010ray diffraction, low\u2010temperature photoluminescence, and Raman scattering to characterize interfacial layers between the barriers and the wells. These interfacial layers are created during the initial stage of growth of the quaternary material as a result of the longer transient for the saturation of the group\u2010III elements flux. The combination of x\u2010ray diffraction and photoluminescence allows a precise determination of the interfacial layer thickness and composition grading and shows that interface roughness is of the order of 1 monolayer. Raman scattering confirms these results and is used to determine values of the sound velocity and of the index of refraction in the quaternary alloy material.Peer reviewed: YesNRC publication: Ye